Patent GB-404984-A (GB)
Title: Improvements in the manufacture and production of unsaturated hydrocarbons from saturated hydrocarbons
IPC: B01J19/00
Filed: 1932-07-25
Abstract: The conversion of saturated hydrocarbons in presence of steam to unsaturated hydrocarbons is effected in apparatus of iron or iron alloys containing less than 2 per cent of nickel, such as iron alloys containing chromium or aluminium, the outside of such apparatus (which is in contact with the heating-gases) being covered with a coating of a steel stable to high temperature such as a chromium nickel steel containing a high proportion of nickel (for example W.C.T.3 steel which contains 20 per cent of nickel). For example a tube of iron or chromium steel may be inserted in a tube of Nichrotherm steel, the junction being made as tight as possible by pressing or rolling; or a tube of chromium steel may be externally coated with nickel and heated to cause a diffusion of the nickel into the outer layer of the tube being effected by heating to a high temperature.  The apparatus for preheating the reaction gases may be of iron or chromium steel without a protective coating.  In this manner olefines may be produced from paraffins such as waste hydrogenation gases and cracking gases. When large quantities of hydrogen sulphide are present, this impurity is preferably removed before the reaction is effected. In an example a gas containing 95 per cent of paraffins (ethane, propane and butane) mixed with steam, is passed through an iron tube surrounded by a chromium nickel steel tube and heated externally so that the internal temperature at the outlet end is about 770 DEG  C.; the reaction product contains 30-35 per cent olefines (ethylene and propylene) and also higher paraffin hydrocarbons.ALSO:The conversion of saturated hydrocarbons in presence of steam to unsaturated hydrocarbons is effected in apparatus of iron or iron alloys containing less than 2 per cent of nickel, such as iron alloys containing chromium or aluminium, the outside of such apparatus (which is in contact with the heating-gases) being covered with a coating of a steel stable to high temperature such as a chromium nickel steel containing a high proportion of nickel (for example WCT3 steel which contains 20 per cent of nickel). For example a tube of iron or chromium steel may be inserted in a tube of Nichrotherm steel, the junction being made as tight as possible by pressing or rolling ; or a tube of chromium steel may be externally coated with nickel a diffusion of the nickel into the outer layer of the tube being effected by heating to a high temperature.  The apparatus for preheating the reaction gases may be of iron or chromium steel without a protective coating.  In this manner olefines may be produced from paraffins such as waste hydrogenation gases and cracking gases.  When large quantities of hydrogen sulphide are present, this impurity is preferably removed before the reaction is effected.  In an example a gas containing 95 per cent of paraffins (ethane, propane, and butane) mixed with steam, is passed through an iron tube surrounded by a chromium nickel steel tube and heated externally so that the internal temperature at the outlet end is about 770 DEG  C.  The reaction product contains 30--35 per cent olefines (ethylene and propylene) and also higher paraffin hydrocarbons.